Elevator control system



May 12, 1931, w. F. EAMES ELEVATOR CONTROL SYSTEM Filed Feb. 4, 1929 aura/var 31-1 INVENTOR W/l/id/fl 5 Fame:

ATTO-RNEY Patented May 12, 1931 UNITED STATES PATENT OFFICE WILLIAM F. EAMES, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC-& MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA ELE ATOR oon'rRoL SYSTEM Myinvention relates to control systems and has particular reference to control systems for elevators, hoists,"and similar motor driven machinery. In the elevator art, it is desirable that the elevator car he made to accelerate and decelerate as rapidly, and to do so between as'wide limits of speed, as is consistent with safety and the comfort of the passengers.

Moreover, in modern high speed elevator systems the normal high speed desired is so great that in making fioor to floor runs it is impossible to accelerate the car to the high speed and to decelerate the car from the high speed within the distance between adjacent floors. Yet it is desirable that the car should always pass a given point adjacent a floor at which a stop is to be made at a constant speed whether the car is at that instant accelerating from zero speed in making a floor to floor run or is decelerating from the high speed in making a run of a greaterdistance.

To utilize a single set of accelerating resistors to control the car on floor to floor runs. and to control the car on runs of greater distance has been found unsatisfactory since when the resistors are adjustedto attain the high speed operation and accurate deceleration therefrom, the same adjustment of resistors will produce an underrunning or overrunning of the floor for a single floor run.

An objectof-my invention is to provide a control system for an elevator in which the acceleration and deceleration rates for a short run and for a longer run of the elevator car are capable of independent adjustment to insure accuracy of landing of the car level with the floors whether the car approaches the floor from one'floor away therefrom or from a greater distance.

Another object of my invention is to provide an elevator system in which the acceleration and deceleration of. the car may be so controlled as to attain, whether on a one-floor run, or on a run pasta plurality offloors, the maximum speed which may be accelerated to and decelerated from with passenger comfort. j r

Another object of my invention is to pro videtacceleration controlling means such that,

having determined the highest intermediate speed to which and from which acceleration and deceleration may be obtained consistent with passenger comfort in making a floor to floor run, and having determined the most desirable rates of acceleration to and deceleration from a higher speed, on accelerating the car from zero speed to its highest speed, or decelerating the car from its highest speed to zero speed, the rates of acceleration and deceleration to the high speed will be sub stantially the same as the rates of acceleration and deceleration employed on theone floor run. 1

My invention will be described with reference to the accompanying drawings, where- Figure 1. is a diagrammatic view of my contro system, as applied to an elevator system, an

Fig. 2 is a diagrammatic View showing the ipeed curves obtained with my control sys- Referring to the drawings, I have illustrated, in Fig. 1, an elevator car C suspended in r the usual manner by a cable Ca, which passes over a hoistin drum D to a suitable counterweight Cw. irectly coupled to the hoistmg drum D is an armature EM of an elevator'motor EM which is provided with a separately-excited field winding EMF. The v armat re EM is connected in loop circuit with t e armature G of a generator G. The generator G is of the cumulative-com ou'nd wound type including a series field GS and a separately-excited field winding GF. A

motor M having its armature M coupled directly to the armature G of the generator G, acts as a driving means for the generator G. The motor M is illustrated as being of the shunt-wound type having its field wlnding MF connected in parallel relation to the armature M.

The illustrated control system is of the automatic landing type wherein the accurate stopping of the elevator car 0 level with any of the floors served by the car is determined by the. operation of suitable inductor relays carried by the car, which cooperate with inductor plates mounted .in the hatchway adjacent to each of the floors. The inductor relays illustrated in the present drawing comprise a high-speed up-inductor relay UB5, a high-speed down-inductor relay DB5 an intermediate speed up-inductor relay U B4, an intermediate speed down-inductor relay DB4, a lower intermediate speed up-inductor the motor under increase in load and to deing the car C to be standing at the lowermost crease the voltagev supplied to the motor under light or overhauling loads in such proportions as to counteract the normal characteristic of the elevator motor to decrease its speed as its load increases.

The direction of rotation and speed of the elevator motor the usual manner by means of an up-direction switch 1, a down-direction switch 2, a plurality of speed relays 3, 4 and 5, a transfer relay 6 and a voltage relay CEMF, which relays operate to include different values of resistance inthe separately-excited field circuit of the generator. I

In the present case, I have employed two separate resistors HSB and LSB, each divided by ordinary taps into three sections 10, 11 and 12, and 13, 14 (and 15, respectively. The resistor HSB is adapted to means hereinafter described in the circuit for. the separately-excited generator field only when the elevator car is decelerating from a high speed to zero, and resistor LSB is adapted to be included by means hereinafter described in the separately-excited generator field circuit when the car decelerates after having operated at said intermediate speed,

My invention may best be described with reference to an assumed operation. Assumfloor, the attendant desiring to start the car upwardly may move the car switch CS in the counter-clockwise direction to energize the up direction switch 1 to thereby cause the car to ascend. The up direction switch extends 1 is ener ized by way of a circuit which om line conductor L1. through conductor 16, normally closed contact memhere 17 of stopping inductor relay SB, con ductor 18, the coil of up direction switch 1, a conductor 19, contact members20, 21 and 22 on car switch Us and conductor 23 to line conductor L2.

Up direction switch 1 when energized EM are suitably controlled in.

e included by completes a circuit-for supplying current to the separately excited field winding for generator G, which circuit extends from line this circuit the car is caused to accelerate to its lowest or-landing speed, as determined by the values of resistors 13, 14 and 15.

The updirection switch 1 when energized also completes a self-holding circuit for itself which circuit extends from line conductor L1 through conductor 16 contact members 17 on-stopping relay SB to the coil of up direction switch '1 as previously described and thence by way of conductor 36, contact-members a on"'up direction switch l'and conductor 37 to line conductor L2. Hence, even.

its off position, the car would continue to operate until relay SB was actuated to open, its contact members 17 as will hereinafter be described. Y

To cause the car to travel at a greater speed, the car switch Cs may be moved to a further position in a counter-clockwise direction to.

though'car switch Cs should be returned to excited generator field I ductors 39 and 40,,contact members 41,21 and conductor L2. 7

Speed relay 3 when energized completes a self holding circuit for itself which extends from line conductor L1 through conductors 24 and 38,- the coil of speed relay 3, conductor 42, contact members a. on speed relay 3, com ductor 43,;contact members 44 on up slowspeed relay UB3, conductor 45 contact 22 on car switch Cs and conductor 23 to line 'members 46 on down slow-speed inductor relay DB'3 and conductors 47 and 23 to line conductor L2.

' The circuit for energizing speed relay 4 extends from line conductor L1 through'conductors 24 and 49, the coil of speed relay 4, conductors 50 and 51, contact inembers 52, 21 and 22 on car switch Cs and conductor 23 to line conductor L2. Speed relay 4 in turncompletes a self-holding circuit for itself whichextends. from line conductorLl through the coil of speed relay 4, as previously described, and thence by way of conductor 53, contact members a on speed relay 4, conductor 54, contact members 55 of up intermediate-speed inductor relay UB4, conductor 56, contact members 57 on down intermediate speed inductor relay DB4 and conductors 58 and 23 to line conductor L2. The energizing circuit for speed relay 5 extends from line conductor L1 through conductors 24 and 60, contact members of voltage nrelay CEMF, conductor 61, the coil of speed relay 5, conductors 62 and 63, contact members 64, 21 and 22 on car switch Cs and conductor 23 to line conductor L2. Speed relay 5 in turn completes a self-holding circuit for itself which extends from line conductor L1 to the coil of speed relay 5, as previously traced, and thence by way of conductor 65,

contact members 20, 41, 52 and 64 respectively to thereby successively energize the up direction switch and speed relays 3, 4 and 5 controlled thereby, it is found to be more convenient to permit him to move the car switch to its extreme position immediately without making it necessary for the attendant to exercise care in the precise movement of the car switch handle.

Provision is made, however, for permitting the attendant to select the speed at which the car will operate dependent upon whether he desires the car to stop at the next adjacent floor or at some floor more distant. This selection is achieved by inserting the contact members of voltage relay CEMF in the energizing circuit for high-speed relay 5 and dewhen the yoltage supplied to the elevator motor reaches a predetermined value preferably in correspondence with the speed of the car above its landing speed as determined by resistors 13, 14 and 15. In fact the interposition of relay CEMF is for the purpose L ever, if the attendant moves thecar switch signing relay CEMF so as to pick up only.

- with comfort to the passengers riding upon thecar and for this reason I have arranged my system in such manner that the car will always accelerate upon the low-speed resistors LSR,

To accomplish this purpose, I have provided a transfer relay 6 having its contact members a and 1) arranged in the circuits of the low speed resistors LSR and the high so speed resistors HSR in such manner as to transfer the generator-field-winding circuit from one of the resistors to the other upon energization or deenergization of the transfer relay. V

The circuit for energizing transfer relay 6 is dependent upon the actuation of high speed relay 5 in such manner that the transfer from one set of resistors to the other occurs upon the determination of whether the car is to make a floor to floor run or a run of a longer distance.

Assuming, in the described conditions of operation, that it is desired to have the car travel from the first floor to the third floor (represented by dotted line marked 3rd floor) and that the attendant holds the car switch Cs in the high speed position .until relay CEMF picks up, it will be apparent that the car C will accelerate to its highest speed as 109 determined by the application of full line Voltage'to the generator field winding GF.

Relay CEMF has its coil connected across the loop circuit conductors 71 and 72, respectively connecting op osite terminals of the generatorarmature and the elevatormotor armature EM in such manner that the relay CEMF will be energized when the voltage produced by the generator G builds up to a predetermined value. This actuation of 110 relay CEMF permits high speed relay 5 to pick up as previously described, and by way 3 of contact members 0 on high speed relay 5,

a circuit is completed for energizing transfer relay 6 which circuit extends from line 1 conductor L1 through conductors 24 and 73,

the coil of transfer relay 6, conductor 74, contact'members a on high speed relay 5, conductors 75 and 76, contact members 6 on up direction switch 1, and conductors 77 and 37 to line conductor L2.

Relay 6 closes its contact members a to cause the circuit for the generator field winding GF to extend through the contact members 6 controlled by speed relays 3, 4 and 5, while contact members I) on relay 6 open to exclude contact members 0 of speed relays 3 and 4 from the field winding circuit. It should be understood that, in order that the circuit for the field Winding GF for the generator shall not be open' during the transfer period, contact members a on relay '6 should be arranged to close just prior to the open- 6 ing of contact members I) on this relay.

will be noted that relay 5, having been 4 energized and having closed its contact members b, has excluded resistor section 12 from the generator field circuit, and hence the field. winding GF will have full line voltage impressed thereon and the car will accelerate to its highest normal speed.

After holding the car switch C8 in high speed position momentarily, the attendant "may return the car switch to off position l without'interrupting the running of the elevator car, since direction switch 1 and speed relays 3, 4 and 5 will be maintained energized through their respective self-holding circuits. However, centering the car switch Will complete. a circuit for energizing the actuating coils of inductor relays UB5, UB4, UB3 and SB to cause these relays to be actuated when they pass their respective inductor plates associated with the third floor.

The circuit for energizing inductor relays UB5, UB4 and UB3'extends from line conductor L1, conductors 24, 25 and 78, contact members i on up-direction switch 1, conductor 79, the coils of inductor relays UB5, UB4

and UB3 in'parallel relation, conductors 80,

81, contact members 82, 83, 21 and 22 on car switch C8, and conductor 23 to line conductor L2. 'The circuit for inductor relay SB extends from line conductor L1, through con-' ductor 84, the coil of relay SB, conductor 85,

contact members 86, 83, 21 and 22 on car switch Cs and'conductor 23 to line conductor L2. Hence, as the car approaches the third floor and-successively passes inductor plates UB5, UB4, UB3 and SB, inductor relays UB5, UB4, UR3'and SB will be successively actuated to open their contact members to drop out speed relays 5, 4 and 3, and up-direction switch 1, respectively, to bring the car to a stop at the thirdfloor level.

It will be observed that, since the car has been operating at high speed,'the deceleration of the car willbe caused by the successive insertion of resistors 12, 11 and 10 in the field winding circuit for the generator G to cause the car to 'decelerate in steps of diminishing speed,each step dependent upon the effective 4 value of-the resistance in each of the resistor sections 12, 11 and 10, respectively.

Referring to Fig. 2, curves 89 and 91 illustrate the relation of car speed to distance traveled as an elevator caris retarded from high speedto'rest. As an illustration,

the deceleration is shown as occurring while the car moves the distance-between the second and third floors. In the figure, the elevator car is shown operating at 'full speed, 600 feet per minute, for example, when passing the vertical line marked 2nd floor. At

a the point 88, the fir st inductor relay UB5,

though speed relay 5 therea tactmembers 0. Hence, speed relay 6 will passes its associated plate UB5 to thereby open the circuit for high-speed relay 5, inserting resistor section 12 in the circuitof the generator field winding GF. Accordingly, the car decelerates along curve 89 to ass the second inductor relay plate' UB4, this point being represented by dotted line 90). At this time, relay UB4 opens its contact members to dropout speed relay 4, inserting resistovsection 11 into the generator field winding circuit, and the'car continues to decelerate along the line 91 until the car passes inductor plate UB3, at which time, inductor relay UB3 opens its contact members 44. The opening of the contact members 44 deenergizes speed relay 3, inserting-resistor section 10 in the generator field winding circuit, and the car further desistance will be proper to. make the car land level with the floor each time it is to be stopped thereat.

It will be observed that the circuit for energizing transfer relay 6 is controlled by actuation of high speed relay 5, but since it is necessary that the high speed resistors HSB shall remain effectively "in the field winding circuit during the entire period of deceleration from high speed until the car is stopped at the floor, I have provided a resistor 87 shunting the contact members 0 of high speed relay 5 in such manner and of such value that while not permitting sufficient currentlto pass to transfer relay 6' to cause this relay to pick up, it will pass suificient current to keep transfer relay 6 energlzed once it has been picked up, even t'er opens itsconremain effective to keep the car under the control of high speed resistors HSB until the :direction switch 1, (or 2 if the car is travel ing downwardly) is opened to bring the car to a stop at the floor.

Assuming, however,"that the car'is standing at the second floor and itis desired to cause the car to make a stop at the third floor, the attendant will move the car switch C8 to. the running position momentarily and immediately thereafter he will return the switch to off position. In this event, voltage relay CEMF will not have been icked up before, the car switch is centere and hence speed relay 5 will not be energized.

Transfer relay 6 will, therefore, remain de-.

attain an intermediate speed determined bythe inclusion of resistor section 15 in the field winding circuit (since this resistor section will not be excluded from the circuit). The car will therefore approach the third floor at the intermediate speed until inductor relay UB4 passes its inductor plate UB4, at which time inductor relay UB4 will open its contact members 55 to deenergize speed relay 4 and insert resistor section 14 in the circuit for the field winding, causing the car to decelerate to a slower speed. As the car continues to approach the floor, inductor relays UB3 and SB will be operated in the manner previously described to deenergize speed relay 3 and direction switch 1 to cause the car to decelerate further on resistor 13 and finally to come to rest at the floor level.

Referring to Fig. 2, I have illustrated a curve'94 which represents the deceleration curve of the elevator when-it is desired to make a stop on a floor to floor run. As the car passes the point 90 at which inductor relay UB4 passes its inductor plate, deceleration will be initiated and the car will slow down along curve 94 until inductor relay UB3 passes its inductor plate (indicated by dotted line. 92), whereupon resistor 13 will be inserted in the field winding circuit and the car will continue to decelerate to make I the stop at the floor level.

As was described with reference to deceleration from high speed, resistor sections'13 and 14 may be adjusted to cause the car to decelerate on any desirable speed curve and it will be noted that adjustment of the low speed resistors LSB to .fit the condition ofa floor to floor run does not in any way disturb the adjustment of-the high speed resistors HSB for deceleration from a longer run.

In this way, it is possiblethat a car, after being installed, may be adjusted to accurately land levelwith the floors when decelerating from high speed and may also be accurately adjusted to land level with the floor when making a floor to floor run. Also, neither of these adjustments will interfere with the other, since the only time that either the high speed resistors HSB or low speed resistors LSB are effective will be at such times as the car has been so-operated as to make the type of run with which the respective resistor is associated. g,

It is to be understood that the described embodiment of my invention is illustrative only and I do not desire to be limited to any of the details shown herein except as defined in the appended claims.

I claim as my invention:

1. In an elevator control system, an ele- "vator car, motive means therefor, means selectively operable to determine the operating speed of said car, means for decelerating said car from one of said speeds to zero speed, means for decelerating said car from another of sad speeds to zero speed, and means dependent upon the speed selected for rendera ing the corresponding decelerating means effective.

2. In an elevator control system, an elevator car, motive means therefor, means selectively operable to determine the operating speed of said car, adjustable means for decelcrating said car from one of said speeds to zero speed, adjustable means for decelerating said car from another of said speeds to zero speed, and means dependent upon the speed selected for rendering the corresponding decelerating means effective.

3. In an elevator control system, an elevator car, motive means therefor, means selectively operable to determine the operating speed of said car, voltage modifying means for decelerating said car from one of said speeds to zero speed, voltage modifying from one speed to zero speed, resistor means for controlling the deceleration of said motive means from another speed to zero speed and means dependent upon the selection of speeds by said selecting means for determining which of said resistor means shall be effective.

5. In an elevator control system, an elevator car, motive means therefor, means selectively operable to determine the operating speed of said car, a plurality of means for controlling the deceleration rate of said car. to zero speed, one for each of a plurality of one for each of a plurality of said speeds and means'dependent upon the speed selected for rendering the associated resistor effective.

7 In an elevator control system, van elevator car operable past a plurality of floors, motive means therefor, means for automatically decelerating said car in steps of diminsaid speeds and means dependent upon the ishing speed to stop said car level with any I of said floors, a plurality of means for determining the-deceleration rate of said car from a plurality of speeds to zero speed, and

means dependent upon the operating speed of said car prior to deceleration for determining which of said rate determining means is to be effective. 8. In an elevator control system, an elevator car operable past a plurality of floors, motive means therefor, means for automatically decelerating said car in steps of dimmishing speed to stop said car level with any of'said floors, a lurality of voltage modifying means for etermining the deceleration rate. of said car from a lurality of speeds to zero speed, and means ependent upon the operating speed of said car prior todeceleration for determining which of said voltage modifying means is to be effective. 9. In a control system for elevators, an elevator operable past a plurality of adiacent floors, a motor therefor, and means controlling the power supplied to said motor for selectively operating said motor at a predetermined intermediate speed and a higher speed, means for controlling deceleration of saidmotor including two separate voltage modifying means,one for decelerating said motor from said higher speed to zero speed,

and the other for decelerating said motor between said predetermined intermediate speed car to operate at one speed for selecting one motive means for operating said motive of said deceleration resistors, and meansoperable upon actuation of said selecting means for maintaining said selected resistor effective until said car is brought substantially to rest. 1

11. In an elevator control system, an elevator car operable past a plurality of floors, mo-

tive means therefor, control means for said motive means for operatlng sald'motlve means at a plurality of speeds, including a plurality of deceleration resistors, means for actuating said control means to select the operating speed of said motive means, transfer means for renderin one of said resistors normally 7 effectlve, an

operable to render another of said resistors effective, and means operable upon selection of one speed by said control actuating means for actuating said transfer means.

' 12. In an elevator control system, an elevator car operable past a plurality of floors, motive means therefor, control means for said means at a plurality of speeds, including a motive means therefor, control meansfor said motive means for operating said motive means at a plurality of speeds, including a pluralityof deceleration resistors, a car switch for actuating said control means to select the operating speed of said motive means, transfer means for rendering one of said resistors normally effective, and o erable to render another of said resistors e ective, and means operable upon selection of one speed by said controlactuating means for actuating said transfer means.

14. In a control system for a motor, a vae riable-v'oltage generator for supplying power to said motor, selective means to control the voltage of said generator to determine a plurality of operating speeds for said motor and to decrease the voltage of said enerator to retard said motor from any of sald operatmg speeds to a certain speed, said control means comprising resistance means to determine the rate of change of the voltage of said generator throughout retardation of said motorfrom one of said operating speeds to said certain speed, additional resistance means to determine the rate of change of the voltage of said generator throughout retardation of said motor from another of said operating speeds to said certain speed, and means dependent upon the operating speed selected for rendering the corresponding resistance means effective. v

15. In a control system for a motor, a variable-voltage generator for supplying power to said motor, selective means to increase and decrease the Volta eof said generator to accelerate and retar said motor between a certain speed and a plurality of higher speeds comprising resistance means to determine the rate of change of the-voltage of said generator during acceleration of. said motor and throughout'retardation of said motor from one of said higher speeds tosaid certain speed, and additional resistance means to determine the rate of chain e ofv the voltage of said generator three out retardation of said motor from anot er of said higher speeds to said certain speed, and means dependent upon which of said higher speeds'is selected for determining which of said resistance means is to be effective throughout retardation.

16. In a control system for a motor, a variable-voltage generator for supplying power to said motor, selective means to increase and decrease the voltage of said generator to accelerate and retard said motor between a certain speed and a plurality of higher speeds comprising resistance means to determine the rate of change of the voltage of said generator during acceleration of said motor and throughout retardation of said motor from one of said higher speeds to said certain speed, additional resistance means to determine the rate of change of the voltage of said generator throughout retardation of said motor from another of said higher speeds to said certain speed, and means rendered efiective by operation of said control means to accelerate said motor to said other higher speed for rendering said resistance means ineffective and for rendering said additional resistance means effective.

17 In a control system for a motor, a variable-voltage generator for. supplying power to said motor, selectively operable means to vary the voltage of said generator to accele ate and retard said motor between a certain speed and a higher speed comprising resistance means to determine the rate of change of the voltage of said genenator throughout acceleration of said motor between said speeds, additional resistance means to determine the rate of change of voltage of said generator throughout retardation of said motor between said speeds, and transfer means controlled by said selectively operable means for determining which of said resistance means is to be effective.

In testimony whereof, I have hereunto subscribed my name this 31st day of January,

WILLIAM F. EAM-ES. 

